Apparatuses designed to constantly record music performance data based on user's performance operation on a keyboard or the like have been known, for example, from Japanese Patent Application Laid-open Publication No. HEI-8-211864. Further, apparatus designed to convert music piece data from a performance data format, such as the MIDI format, to an audio data format have been known, for example, from Japanese Patent Application Laid-open Publication No. 2004-45706. Furthermore, music apparatuses designated to protect a copyright of automatically-performed music piece data have been known, for example, from Japanese Patent Application Laid-open Publication No. 2003-58150.
It is conceivable to constantly record tone signals, formed on the basis of user's performance operation, in a digital audio format while simultaneously reproducing automatic performance data. However, in the conventionally-known techniques, no consideration has been given as to appropriate measures in cases where automatic performance data, of which protection of the copyright is required, are reproduced during the constant recording.